What Is It?
Amenorrhea is when a woman of childbearing age fails to menstruate. A woman normally menstruates every 23 to 35 days.
The part of the brain called the hypothalamus regulates the menstrual cycle. The hypothalamus stimulates the pituitary gland. The pituitary gland lies just below the hypothalamus at the base of the brain.
The pituitary gland releases two hormones that regulate the female reproductive cycle. They are luteinizing hormone (LH) and follicle-stimulating hormone (FSH).